Air-cooled deflecting plate



April 2G? 1926. mmm

D. F: GRAHAME AIR COOLED DEFLECTTNG PLATE Filed April 25, 1924 a., Qv-f- L Patented Apr. 20, 1926.

UNITED STATES l Tseran PATENT OFFICE.

DALLAS F. GRAHAME, OF WORCESTER, MASSACHUSETTS, ASSIG-NOR TO RILEY'STOKER CQRPORATION, OF WORCESTER, MASSACHUSETTS, A CORPORATION F ,MASSA- CI-I'USETTS.

AIR-COOLED DEFLECTING PLATE.

Application` led April 25, 1824.

To all whom 'it may concern:

Be it known that I, DALLAS F. GRAHAME, a subject 'of the King of Grreat Britain, residing at YVOrcester, in the county of Worcester and State of Massachusetts, have invented certain new and useful Improvements in Air-Cooled '.Deflecting Plates, of which the following is a full, clear, and exact specication. f

My invention relates to underfeed stokers and more particularly to the construction of the throat thru which the fuel is fed into the furnace.

In an underfeed stoker as usually constructed, a fuel hopper is located close to the furnace wall and a reciprocating ram employed to push fuel from the bottom of the hopper thru a throat into the furnace. There is a tendency in such a furnace for gases to be formed in the throat by a partial decomposition of the fuel by the intense heat radiated from the adjacent combustion zone, -and under certain conditions this gas may travel back thru the throat into the fuel hopper and so issue into the air breathed by the furnace attendants. Moreover, the -iron parts forming the throat which are nearest the lire are subjected to a high temperature and are likely to be burned away and require replacements at frequent intervals.

It is the main purpose of my invention to provide a construction for the throat of an underfeed sto'ker which will obviate any danger of escape of furnace gases and which will be air-cooled and so constructed asto transmit the heat readily to the cooling medium and therefore last for a long time.

A further object of my invention is to provide a unitary and simple construction which may be easily and cheaply manufactured and readily installed in a stoker furnace.

With these and other objects in view as will be apparent to one skilled in the art, my invention resides in the combination of parts set forth in the specification and covered by the claims appended hereto.

Referring to the drawings in which like reference numerals indicate like parts:

Fig. 1` is a fragmentary vertical elevation, partly in section, of a furnace embodying my invention; and

Fig. 2 is a perspective view, partly broken Serial' No. 709,054.

away, of the air cooled delectingplate and its cover.

'In accordance with my invention, I pro-p vide a stoker with a front wall air box having a coal deflecting plate which forms the upper half of the fuel feeding throat, and I provide this plate with ribs and so arrange the parts that heat may be readily transmitted from the throat of the stoker to the air within the box above the ldeflecting plate.

Referring to the drawings illustrating one embodiment of my invention, I have there shown the front wall of a Stoker furnace within which the fuel'bed 11 is carried on a suitable grate structure. The fuel is fed thru a throat or opening formed in the brick wall from a hopper 12 by means of a suitable mechanism 13 comprising a ram operated by a steam cylinder, as is well known in the art.

The lower half of the throat.` thru which P the fuel enters the furnace comprises a concave, substantially semi-cylindrical member 15 which has two upwardly and inwardly sloping ridges 16 arranged to support the upper half of the throat. As illustra-ted particularly in Fig. 2, this upper part of the throat comprises a casting 18 which has downwardly depending flanges 19 and a wall 2O forming a substantially semi-cylindrical downwardly concaved portion. The flanges 19 rest on the shoulders 16 of the lowery member 15. The wall 20 slopes upwardly toward the inside of the furnace, the angle of inclination being sufficient steep so that any gases which may accumulate. in the throat will naturally flow along this wall until they reach the combustion Zone where they are burned. i

In order to form an air box arranged to absorb heat from these throat walls 19 and 20, I extend the flanges 19 upwardly to form two vertical walls 22, the upper edges of which are substantially horizontal. The brick work of the front wall of the furnace is supported by these walls 22, a cover plate 24 being preferably provided to aid in holding the brick work in place. The front plate 25 of the furnace constitutes the front wall of the air box and the wall 2O vis extended upwardly at the inner end as a short wall 26 to meet the cover plate 24, so that the latter rests on the plane top edges of three walls of the casting 18.

The air box is connected by a suitable pipe 27 with the air chamber beneath the stoker so that air may be conducted thereto under a suitable pressure. An opening 28 is provided in the side wall 22 so that the plpe 27 may communicate with the space within. Provision/is made for egress of the air from this chamber by forming grooves 30 in the upper edge of the wall 26 which serves as openings between the wall and the cover plate, whereby air within the chamber may issue into the combustion zone of the furnace and aid in the combustion as well as keep the adjacent parts ofthe furnace structure cool.

A series of ribs or flanges 82 are provided on the inside of the air box in order that heat absorbed by the unitary metal casting may be quickly transferred to the air within. It will also be noted that the integral flanges 19 extending a considerable distance around the throat of the fuel entrance also to serve to transfer heat absorbed from the fuel bed directly to the wall 2O and flanges 32 and thence to the circulating air.

These side flanges and the ribs are particularly important in this construction owing to the intense heat to which this metal unit is subjected. It will also be noted that the ribs 32 terminate at their upper ends in vertical ribs 33 which serve to conduct heat striking the wall 26 into the air chamber within. This part of the metal unit is subjected to intense heat and such provision is important for preserving the life of the delecting plate.

It will therefore be seen that I have provided a simple construction which will serve various purposes in a furnace. In addition to forming a deflecting plate arranged to keep the furnace gases from passing out through the fuel hopper, `the casting 18 serves as a part of the front wall of the stoker opposite the combustion zone. It is cooled by the constant stream of air passing upwardly through pipe 27 and this cooling effect is amplified by the peculiar construction, including flanges 19 and ribs 32 and 33, which I employ. The air outlets 30 serve to transmit a cooling current to a point adjacent theinner wall 26. These openings also constitute tuyeres thru which air is fed into the furnace, but I prefer to make them small and to circulate onlyeso much air as is required to cool the partsv of th-e'casting sufliciently for protective purposes.

Having thus described my invention, what I claim asy new and desire to secure by Letters Patent is:

1. A unitary device for use in an underfeed stoker as a gas deiiecting and cooling wall defining a portion of the throat through which fuel is fed into the furnace, comprising an upwardly inclined concave wall which forms a substantial portion of the exposed area ofsaid throat and the bottom of an air chamber, parallelside plates integrally connected with said wall and forming therewith the side walls of the air chamber, said plates having substantially horizontal 'tops arranged to support a furnace wall-thereon, and ribs on the bottom wall of the air chamber to aid in transferring heat from the concave wall of the throat to the air above.

2. In an underfeed stoker furnace, a throat construction for introducing fuel into the furnace comprising a concave wall having an upwardly inclined top and lateral depending portions forming a substantial part of the total throat area, upwardly projecting walls formed integrally therewithk which define the sides of an air chamber, a front plate for said chamber, a cover resting on the side walls and arranged to supporta furnace wall thereon, a rear wall for said chamber having a passage therethrough to the fuel bed, the top wall of the throat constituting the bottom of the air chamber and having heat conducting ribs projecting upwardly therefrom into the air chamber, and means permitting the circulation of air through said chamber.

Signed at Worcester, Massachusetts, this 24th day of April, 1924.

DALLAS F. .GRAHAME 

